Showing papers in "Hydrometallurgy in 1994"

TL;DR: In this article, several organic acids were tested and compared for their ability to solubilise nickel and iron from Greek laterite ores, and the results were also compared with sulphuric acid leaching under the same conditions.

TL;DR: In this article, a reductive leaching process for manganese dioxide using sucrose as the reducing agent in sulphuric acid solution was studied, and 16 unreplicated tests have been carried out to study five factors at two levels: sulfuric acid concentration, sucrose concentration, particle size range of the mineral, mixing conditions and temperature.

TL;DR: The IBES (Indirect Bioleaching with Effect Separation) process improves the kinetics of the bio-leaching by means of a physical separation of the chemical and biological effects involved in what is called the indirect contact mechanism as mentioned in this paper.

TL;DR: In this article, the authors investigated the influence of NaCl, NaNO3, Na2SO4 and NaSCN on the performance of cobalt extraction in benzene.

TL;DR: In this paper, the kinetics of chalcopyrite oxidation by potassium dichromate in sulphuric acid were investigated and the activation energy was 48-54 kJ/mol.

TL;DR: In this paper, the behaviour of the phosphine oxides Cyanex 923 and Cylonex 925 in the recovery of gold(I) from cyanide solutions is described.

TL;DR: In this paper, the cyanidation of argentian natrojarosite in alkaline medium shows an induction period, followed by a conversion period, and the conversion period is characterized by the unreacted core model, the reaction halo is formed by amorphous hydroxides and the core by jarosite.

TL;DR: In this paper, the results of the extraction of Zn(II, Cu(II) and Cd(II), from nitrate and chloride solutions at 0.1 M ionic strength and 25°C by the Levextrel impregnated resin Lewatit 1026 Oc containing di(2-ethylhexyl)-phosphoric acid (DEHPA) were presented.

TL;DR: In this article, a new technology for uranium and rare earth recovery from wet process phosphoric acid (WPA) in a one-cycle extraction-stripping method was simple and easy to control because only acidic media were involved.

TL;DR: In this article, the authors investigated the leaching of synthetic Ag2S in FeCl3-HCl and Fe2(SO4)3H2SO4 media using the rotating disk technique.

TL;DR: In this paper, the extraction of gold from cyanide solutions by the commercially available phosphine oxide, Cyanex 921, was described, and the effect of several variables, such as equilibration time, temperature, diluent aromaticity, extractant concentration and the ionic strength of the aqueous phase was discussed.

TL;DR: In this paper, the co-deposition of metal impurities (Cu, Ni and Sb) with zinc from industrial acid sulphate solutions with a high concentration of impurities was studied at a current density of 1000 A m −2, without, and in the presence of, specific combinations of the following surfactants: nonylphenolpolyethylene glycol (D1), dinaphthylmethane-4,4′-disulphonic acid (D2), and polyethylylene glycol with molecular weight 400 (D3).

TL;DR: In this article, the kinetics of the leaching processes were investigated and the optimum leaching conditions were determined, and the optimal conditions were derived for different types of leaching.

TL;DR: In this paper, a series of amide extractants and their properties as potential metal extractants for the rare earth metal neodymium were assessed and a systematic investigation was carried out on the extraction properties of the extractants synthesized using the NE ion Nd 3+ to monitor the extraction of a typical trivalent rare earth species.

TL;DR: In this paper, the authors explored the oxidation of As(III) to As(V) using hydrogen peroxide in water solution at initial concentrations of As (III) of 0.3, 3.0, 15.0 g·l −1 exhibiting 50% and 100% excess H 2 O 2 over the stoichiometric amount at 25°C in an acid medium of pH 2 and alkaline medium with pH 11.

TL;DR: In this article, the effect of neutral organophosphorus compounds on the solvent extraction of cadmium and zinc by solutions of various carboxylic acids in xylene is reported.

TL;DR: In this paper, N 2 -substituted N 1 -phenylbenzamidines and N 1-disubstitized N -benzoyl thiourea derivatives, which contain donor S, N and O atoms, have been studied as carriers for the facilitated transport of Pd(II).

TL;DR: In this paper, the infrared spectra of the above extractants were examined and the carbonyl and CN bond stretching regions were monitored for changes as nitric acid or Nd 3+ was extracted.

TL;DR: In this paper, the possibility of gold and silver extraction from products obtained during treatment of copper anodic slimes has been investigated through the construction of potential-pH diagrams for Au-CS(NH2)2-H2O and Ag-CS-NH2-2-O systems, and the effect of leach parameters such as thiourea and ferric-ion concentrations in the solution and level of the redox potential were considered.

TL;DR: In this article, the effects of Dowfroth and Saponin, alone and in various combinations with antimony and with manganese and magnesium sulphates, on zinc deposition current efficiency and on the morphology and orientation of 24 h zinc deposits electrowon at 430 A/m2 and 35°C from synthetic acid sulphate electrolyte were determined.

TL;DR: In this paper, the effects of calcination temperature, solution concentration, reaction temperature and pre-hydration on the leaching kinetics of calcined colemanite in ammonium chloride solutions were evaluated.

TL;DR: In this paper, the effect of triisobutylphosphine sulphide (TIBPS) to 3,5-diisopropylsalicylic acid (DIPSA) was investigated.

TL;DR: In this paper, the effects of cyanidation conditions (pH, time, particle size of the ore, additives to the leach, and oxidative pre-treatments) at ambient temperatures on the extraction of platinum, palladium and gold from samples from the Coronation Hill deposit, Australia, were studied.

TL;DR: The results of a series of fundamental and applied researches into mineral acid and metal salt extraction by salts of organic acids and organic bases (binary extractants) have been generalized and systematized as mentioned in this paper.

TL;DR: In this article, the extraction of Fe(III), Co(II), Ni(II) and Cu(II ) from aqueous solutions of various pH values and complexing agents using 1phenyl-3-methyl-4-(p-nitrobenzoyl)-5-pyrazolone has been investigated.

TL;DR: In this article, the influence of diluent on extraction of TeCl 4 and SeOCl 2 from 4.5 M aqueous hydrochloric acid solution by using 5 vol% and 30 vol% tri-n butyl phosphate (TBP) was studied at 1 O / A volume ratio and 303 K.

TL;DR: In this paper, the photo-isomerization and photo-degradation of 2-hydroxy-5-methylbenzophenone (Z )-oxime in ethanol, octane, toluene and a mixture of octane and toluenes under an exposure to UV light is studied.

TL;DR: In this article, the effects of four organic formulations on morphology, texture, dendrite formation and impurity content of electro-refined copper deposits were determined and compared and the influence of these additives on the quality of deposits during current reversal was also examined.

TL;DR: In this paper, a separation technique has been investigated in laboratory scale batch experiments, involving gold adsorption on powdered activated carbon; the latter was compared with granular carbon, and the promising results obtained were further studied by means of electrokinetic measurements.

TL;DR: In this paper, the partition of gold(I) between aqueous cyanide solutions and solutions of primary amine, Primene JMT, in xylene was studied at various pH values, metal and extractant concentrations, temperatures and equilibration times.